1,181 research outputs found

    The Sequential Relationship of Body Oscillations in the Paper Wasp, \u3ci\u3ePolistes Fuscatus\u3c/i\u3e (Hymenoptera: Vespidae)

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    Three kinds of body oscillations by foundresses of the paper wasp, Polistes fuscatus, were analyzed from 100 h of videotapes of 17 multiple- and 16 single-foundress, preworker colonies. The three kinds of oscillations were observed to be temporally proximate only after prey returns. Their sequential occurrence was always antennal drumming (AD), abdominal wagging (AW), and lateral vibration (LV). This sequence is consistent with the hypothesized communicative meanings of ADs, AWs, and LVs. In particular, ADs may signal larvae to withold salivary secretions prior to receiving a liquid meal from an adult female; oscillations AW and LV may signal larvae to secrete and withold saliva, respectively, Additional studies are required to provide causal evidence of the communicative meanings of ADs, AWs, and LVs

    The Sequential Relationship of Body Oscillations in the Paper Wasp, \u3ci\u3ePolistes Fuscatus\u3c/i\u3e (Hymenoptera: Vespidae)

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    Three kinds of body oscillations by foundresses of the paper wasp, Polistes fuscatus, were analyzed from 100 h of videotapes of 17 multiple- and 16 single-foundress, preworker colonies. The three kinds of oscillations were observed to be temporally proximate only after prey returns. Their sequential occurrence was always antennal drumming (AD), abdominal wagging (AW), and lateral vibration (LV). This sequence is consistent with the hypothesized communicative meanings of ADs, AWs, and LVs. In particular, ADs may signal larvae to withold salivary secretions prior to receiving a liquid meal from an adult female; oscillations AW and LV may signal larvae to secrete and withold saliva, respectively, Additional studies are required to provide causal evidence of the communicative meanings of ADs, AWs, and LVs

    Behavioral Differences Between Two Recently Sympatric Paper Wasps, the Native \u3ci\u3ePolistes Fuscatus\u3c/i\u3e and the Invasive \u3ci\u3ePolistes Dominulus\u3c/i\u3e

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    Polistes dominulus (Christ), an old world paper wasp, was introduced into the eastern United States in the 1970s and has been rapidly spreading westward. Recently, it has displaced the native Polistes fuscatus (F.) in at least some areas of Michigan. In order to understand why P. dominulus has been so successful, several behavioral attributes were compared between P. dominulus and P. fuscatus at a Michigan field site that contained colonies of both species nest- ing semi-naturally in plywood nestboxes. Preworker colonies of P. dominulus had a significantly greater tendency to store nectar (and had significantly higher proportions of cells with nectar) than preworker colonies of P. fuscatus. This finding may explain the higher survivorship of P. dominulus foundresses reported in a previous study. P. dominulus also had a significantly greater tendency to build vertical nests and had significantly more pedicels per comb and per cell than P. fuscatus. These findings suggest that compared to P. fuscatus, P. dominulus may have more flexibility in the positioning of its combs and, because of a possibly stronger attachment of the comb to a substrate, may be less susceptible to bird predation. The higher winter survivorship reported for P. fuscatus over P. dominulus in a previous study does not appear to be due to differences in the proportions of gynes stranded on their nests late in the fall. Finally, behavioral evidence from videography was consistent with previous reports that P. dominulus is not replacing P. fuscatus through direct agonistic interactions

    Comparative Foraging Behavior of Six Sympatric Woodpecker Species

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    The foraging behavior of six sympatric woodpecker species was studied between March 18 and April 24, 1975, in an oak-hickory woodland in Iowa City, Iowa. The six species of woodpeckers did not differ significantly in the parameter of mean foraging height, but did forage on different mean limb diameters. Other differences in foraging behavior noted between species were dead/live tree selection, sap utilization, and ground foraging. Significant differences in foraging behavior were also recorded between sexes of downy woodpeckers. Males tended to forage higher in trees and on smaller limbs than conspecific females

    Retractable Visual Indicator Assembly

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    A retractable indicator assembly may be mounted on a container which transmits air through the container and removes deleterious gases with an activated charcoal medium in the container. The assembly includes: an elongate indicator housing has a chamber therein; a male adaptor with an external threads is used for sealing engagement with the container; a plug located at the upper end of the housing; a housing that includes a transparent wall portion for viewing at least a portion of the chamber; a litmus indicator, moveable by a retractable rod from a retracted position within the container to an extended position within the chamber of the housing; and an outer housing that is secured to the upper end of the rod, and protects the indicator housing while the litmus indicator is in its normally retracted position. The assembly may be manually manipulated between its extended position wherein the litmus indicator may be viewed through the transparent wall of the indicator housing, and a retracted position wherein the outer housing encloses the indicator housing and engages the exterior of the container

    Behavioral Differences Between Two Recently Sympatric Paper Wasps, the Native \u3ci\u3ePolistes Fuscatus\u3c/i\u3e and the Invasive \u3ci\u3ePolistes Dominulus\u3c/i\u3e

    Get PDF
    Polistes dominulus (Christ), an old world paper wasp, was introduced into the eastern United States in the 1970s and has been rapidly spreading westward. Recently, it has displaced the native Polistes fuscatus (F.) in at least some areas of Michigan. In order to understand why P. dominulus has been so successful, several behavioral attributes were compared between P. dominulus and P. fuscatus at a Michigan field site that contained colonies of both species nest- ing semi-naturally in plywood nestboxes. Preworker colonies of P. dominulus had a significantly greater tendency to store nectar (and had significantly higher proportions of cells with nectar) than preworker colonies of P. fuscatus. This finding may explain the higher survivorship of P. dominulus foundresses reported in a previous study. P. dominulus also had a significantly greater tendency to build vertical nests and had significantly more pedicels per comb and per cell than P. fuscatus. These findings suggest that compared to P. fuscatus, P. dominulus may have more flexibility in the positioning of its combs and, because of a possibly stronger attachment of the comb to a substrate, may be less susceptible to bird predation. The higher winter survivorship reported for P. fuscatus over P. dominulus in a previous study does not appear to be due to differences in the proportions of gynes stranded on their nests late in the fall. Finally, behavioral evidence from videography was consistent with previous reports that P. dominulus is not replacing P. fuscatus through direct agonistic interactions

    Measurement of the cross-section and charge asymmetry of WW bosons produced in proton-proton collisions at s=8\sqrt{s}=8 TeV with the ATLAS detector

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    This paper presents measurements of the W+μ+νW^+ \rightarrow \mu^+\nu and WμνW^- \rightarrow \mu^-\nu cross-sections and the associated charge asymmetry as a function of the absolute pseudorapidity of the decay muon. The data were collected in proton--proton collisions at a centre-of-mass energy of 8 TeV with the ATLAS experiment at the LHC and correspond to a total integrated luminosity of 20.2~\mbox{fb^{-1}}. The precision of the cross-section measurements varies between 0.8% to 1.5% as a function of the pseudorapidity, excluding the 1.9% uncertainty on the integrated luminosity. The charge asymmetry is measured with an uncertainty between 0.002 and 0.003. The results are compared with predictions based on next-to-next-to-leading-order calculations with various parton distribution functions and have the sensitivity to discriminate between them.Comment: 38 pages in total, author list starting page 22, 5 figures, 4 tables, submitted to EPJC. All figures including auxiliary figures are available at https://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/STDM-2017-13

    Search for chargino-neutralino production with mass splittings near the electroweak scale in three-lepton final states in √s=13 TeV pp collisions with the ATLAS detector

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    A search for supersymmetry through the pair production of electroweakinos with mass splittings near the electroweak scale and decaying via on-shell W and Z bosons is presented for a three-lepton final state. The analyzed proton-proton collision data taken at a center-of-mass energy of √s=13  TeV were collected between 2015 and 2018 by the ATLAS experiment at the Large Hadron Collider, corresponding to an integrated luminosity of 139  fb−1. A search, emulating the recursive jigsaw reconstruction technique with easily reproducible laboratory-frame variables, is performed. The two excesses observed in the 2015–2016 data recursive jigsaw analysis in the low-mass three-lepton phase space are reproduced. Results with the full data set are in agreement with the Standard Model expectations. They are interpreted to set exclusion limits at the 95% confidence level on simplified models of chargino-neutralino pair production for masses up to 345 GeV

    Search for direct stau production in events with two hadronic tau-leptons in root s=13 TeV pp collisions with the ATLAS detector

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    A search for the direct production of the supersymmetric partners ofτ-leptons (staus) in final stateswith two hadronically decayingτ-leptons is presented. The analysis uses a dataset of pp collisions corresponding to an integrated luminosity of139fb−1, recorded with the ATLAS detector at the LargeHadron Collider at a center-of-mass energy of 13 TeV. No significant deviation from the expected StandardModel background is observed. Limits are derived in scenarios of direct production of stau pairs with eachstau decaying into the stable lightest neutralino and oneτ-lepton in simplified models where the two staumass eigenstates are degenerate. Stau masses from 120 GeV to 390 GeV are excluded at 95% confidencelevel for a massless lightest neutralino

    Bolivia and the paradoxes of democratic consolidation

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    In Bolivia from the 1990s on, two presidents were ousted by popular protests, and protests were rampant. The protests expressed a growing discontent not only with successive administrations and their policies but with politics itself. The polity failed to built trust in democracy, ignored or repressed protests, and thus contributed to a process of democratic "deconsolidation." The main factors were corruption and the reluctance of the traditional political parties to discuss the neoliberal economic model. As a result, the current administration of Evo Morales faces two challenges: to change economic policies and to repair the support for democracy
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